I would disconet the battery overnight to the let the ECU clear up. Later on, the ECU can be tested by disconeting components and checking the codes to make sure the respective code came up for that component. For example, if a disconect the air mass flow meater and start the car( it would run like shit), I would get a code or check engine light for this component. YOU CAN ALSO TEST THE ECU BY INSERTING THE PIN READING ON THE APPROPIATE SYSTEM LIKE FUEL AND PRESSSING THE PUSH BUTTOM 3 TIMES TO TEST COMPONENTS.